mirror of
https://github.com/GSA/notifications-admin.git
synced 2026-04-19 00:31:35 -04:00
There are basically two kinds of 4G masts: Frequency | Range | Bandwidth ----------|-------------|---------------------------------- 800MHz | Long (500m) | Low (can handle a bit of traffic) 1800Mhz | Short (5km) | High (can handle lots of traffic) The 1800Mhz masts are better in terms of how much traffic they can handle and how fast a connection they provide. But because they have quite short range, it’s only economical to install them in very built up areas†. In more rural areas the 800MHz masts are better because they cover a wider area, and have enough bandwidth for the lower population density. The net effect of this is that cell broadcasts in rural areas are likely to bleed further, because the masts they are being broadcast from are less precise. We can use population density as a proxy for how likely it is to be covered by 1800Mhz masts, and therefore how much bleed we should expect. So this commit varies the amount of bleed shown based on the population density. I came up with the formula based on 3 fixed points: - The most remote areas (for example the Scottish Highlands) should have the highest average bleed, estimated at 5km - An town, like Crewe, should have about the same bleed as we were estimating before (1.5km) – Pete D thinks this is about right based on his knowledge of the area around his office in Crewe - The most built up areas, like London boroughs, could have as little as 500m of bleed Based on these three figures I came up with the following formula, which roughly gives the right bleed distance (`b`) for each of their population densities (`d`): ``` b = 5900 - (log10(d) × 1_250) ``` Plotted on a curve it looks like this: This is based on averages – remember that the UI shows where is _likely_ to receive the alert, based on bleed, not where it’s _possible_ to receive the alert. Here’s what it looks like on the map: --- †There are some additional subtleties which make this not strictly true: - The 800Mhz masts are also used in built up areas to fill in the gaps between the areas covered by the 1800Mhz masts - Switching between masts is inefficient, so if you’re moving fast through a built up area (for example on a train) your phone will only use the 800MHz masts so that you have to handoff from one mast to another less often
255 lines
7.8 KiB
Python
255 lines
7.8 KiB
Python
import itertools
|
||
from datetime import datetime, timedelta
|
||
|
||
from notifications_utils.polygons import Polygons
|
||
from notifications_utils.template import BroadcastPreviewTemplate
|
||
from orderedset import OrderedSet
|
||
from werkzeug.utils import cached_property
|
||
|
||
from app.broadcast_areas import CustomBroadcastAreas, broadcast_area_libraries
|
||
from app.formatters import round_to_significant_figures
|
||
from app.models import JSONModel, ModelList
|
||
from app.models.user import User
|
||
from app.notify_client.broadcast_message_api_client import (
|
||
broadcast_message_api_client,
|
||
)
|
||
|
||
|
||
class BroadcastMessage(JSONModel):
|
||
|
||
ALLOWED_PROPERTIES = {
|
||
'id',
|
||
'service_id',
|
||
'template_id',
|
||
'content',
|
||
'service_id',
|
||
'created_by',
|
||
'personalisation',
|
||
'starts_at',
|
||
'finishes_at',
|
||
'created_at',
|
||
'approved_at',
|
||
'cancelled_at',
|
||
'updated_at',
|
||
'created_by_id',
|
||
'approved_by_id',
|
||
'cancelled_by_id',
|
||
}
|
||
|
||
libraries = broadcast_area_libraries
|
||
|
||
def __lt__(self, other):
|
||
if self.starts_at and other.starts_at:
|
||
return self.starts_at < other.starts_at
|
||
if self.starts_at and not other.starts_at:
|
||
return True
|
||
if not self.starts_at and other.starts_at:
|
||
return False
|
||
if self.updated_at and not other.updated_at:
|
||
return self.updated_at < other.created_at
|
||
if not self.updated_at and other.updated_at:
|
||
return self.created_at < other.updated_at
|
||
if not self.updated_at and not other.updated_at:
|
||
return self.created_at < other.created_at
|
||
return self.updated_at < other.updated_at
|
||
|
||
@classmethod
|
||
def create(cls, *, service_id, template_id):
|
||
return cls(broadcast_message_api_client.create_broadcast_message(
|
||
service_id=service_id,
|
||
template_id=template_id,
|
||
content=None,
|
||
reference=None,
|
||
))
|
||
|
||
@classmethod
|
||
def create_from_content(cls, *, service_id, content, reference):
|
||
return cls(broadcast_message_api_client.create_broadcast_message(
|
||
service_id=service_id,
|
||
template_id=None,
|
||
content=content,
|
||
reference=reference,
|
||
))
|
||
|
||
@classmethod
|
||
def from_id(cls, broadcast_message_id, *, service_id):
|
||
return cls(broadcast_message_api_client.get_broadcast_message(
|
||
service_id=service_id,
|
||
broadcast_message_id=broadcast_message_id,
|
||
))
|
||
|
||
@property
|
||
def areas(self):
|
||
library_areas = self.get_areas(areas=self._dict['areas'])
|
||
|
||
if library_areas:
|
||
if len(library_areas) != len(self._dict['areas']):
|
||
raise RuntimeError(
|
||
f'BroadcastMessage has {len(self._dict["areas"])} areas '
|
||
f'but {len(library_areas)} found in the library'
|
||
)
|
||
return library_areas
|
||
|
||
return CustomBroadcastAreas(
|
||
areas=self._dict['areas'],
|
||
polygons=self._dict['simple_polygons'],
|
||
)
|
||
|
||
@property
|
||
def parent_areas(self):
|
||
return sorted(set(self._parent_areas_iterator))
|
||
|
||
@property
|
||
def _parent_areas_iterator(self):
|
||
for area in self.areas:
|
||
for parent in area.parents:
|
||
yield parent
|
||
|
||
@cached_property
|
||
def polygons(self):
|
||
return Polygons(
|
||
list(itertools.chain(*(
|
||
area.polygons for area in self.areas
|
||
)))
|
||
)
|
||
|
||
@cached_property
|
||
def simple_polygons(self):
|
||
return self.get_simple_polygons(areas=self.areas)
|
||
|
||
@cached_property
|
||
def simple_polygons_with_bleed(self):
|
||
polygons = Polygons(
|
||
list(itertools.chain(*(
|
||
area.simple_polygons_with_bleed for area in self.areas
|
||
)))
|
||
)
|
||
# If we’ve added multiple areas then we need to re-simplify the
|
||
# combined shapes to keep the point count down
|
||
return polygons.smooth.simplify if len(self.areas) > 1 else polygons
|
||
|
||
@property
|
||
def reference(self):
|
||
if self.template_id:
|
||
return self._dict['template_name']
|
||
return self._dict['reference']
|
||
|
||
@property
|
||
def template(self):
|
||
return BroadcastPreviewTemplate({
|
||
'template_type': BroadcastPreviewTemplate.template_type,
|
||
'name': self.reference,
|
||
'content': self.content,
|
||
})
|
||
|
||
@property
|
||
def status(self):
|
||
if (
|
||
self._dict['status']
|
||
and self._dict['status'] == 'broadcasting'
|
||
and self.finishes_at < datetime.utcnow().isoformat()
|
||
):
|
||
return 'completed'
|
||
return self._dict['status']
|
||
|
||
@cached_property
|
||
def created_by(self):
|
||
return User.from_id(self.created_by_id) if self.created_by_id else None
|
||
|
||
@cached_property
|
||
def approved_by(self):
|
||
return User.from_id(self.approved_by_id)
|
||
|
||
@cached_property
|
||
def cancelled_by(self):
|
||
return User.from_id(self.cancelled_by_id)
|
||
|
||
@property
|
||
def count_of_phones(self):
|
||
return round_to_significant_figures(
|
||
sum(area.count_of_phones for area in self.areas),
|
||
1
|
||
)
|
||
|
||
@property
|
||
def count_of_phones_likely(self):
|
||
area_estimate = self.simple_polygons.estimated_area
|
||
bleed_area_estimate = self.simple_polygons_with_bleed.estimated_area - area_estimate
|
||
return round_to_significant_figures(
|
||
self.count_of_phones + (self.count_of_phones * bleed_area_estimate / area_estimate),
|
||
1
|
||
)
|
||
|
||
def get_areas(self, areas):
|
||
return broadcast_area_libraries.get_areas(
|
||
*areas
|
||
)
|
||
|
||
def get_simple_polygons(self, areas):
|
||
polygons = Polygons(
|
||
list(itertools.chain(*(
|
||
area.simple_polygons for area in areas
|
||
)))
|
||
)
|
||
# If we’ve added multiple areas then we need to re-simplify the
|
||
# combined shapes to keep the point count down
|
||
return polygons.smooth.simplify if len(areas) > 1 else polygons
|
||
|
||
def add_areas(self, *new_areas):
|
||
areas = list(OrderedSet(
|
||
self._dict['areas'] + list(new_areas)
|
||
))
|
||
simple_polygons = self.get_simple_polygons(areas=self.get_areas(areas=areas))
|
||
self._update(areas=areas, simple_polygons=simple_polygons.as_coordinate_pairs_lat_long)
|
||
|
||
def remove_area(self, area_to_remove):
|
||
areas = [
|
||
area for area in self._dict['areas']
|
||
if area != area_to_remove
|
||
]
|
||
simple_polygons = self.get_simple_polygons(areas=self.get_areas(areas=areas))
|
||
self._update(areas=areas, simple_polygons=simple_polygons.as_coordinate_pairs_lat_long)
|
||
|
||
def _set_status_to(self, status):
|
||
broadcast_message_api_client.update_broadcast_message_status(
|
||
status,
|
||
broadcast_message_id=self.id,
|
||
service_id=self.service_id,
|
||
)
|
||
|
||
def _update(self, **kwargs):
|
||
broadcast_message_api_client.update_broadcast_message(
|
||
broadcast_message_id=self.id,
|
||
service_id=self.service_id,
|
||
data=kwargs,
|
||
)
|
||
|
||
def request_approval(self):
|
||
self._set_status_to('pending-approval')
|
||
|
||
def approve_broadcast(self):
|
||
self._update(
|
||
starts_at=datetime.utcnow().isoformat(),
|
||
finishes_at=(
|
||
datetime.utcnow() + timedelta(hours=4, minutes=0)
|
||
).isoformat(),
|
||
)
|
||
self._set_status_to('broadcasting')
|
||
|
||
def reject_broadcast(self):
|
||
self._set_status_to('rejected')
|
||
|
||
def cancel_broadcast(self):
|
||
self._set_status_to('cancelled')
|
||
|
||
|
||
class BroadcastMessages(ModelList):
|
||
|
||
model = BroadcastMessage
|
||
client_method = broadcast_message_api_client.get_broadcast_messages
|
||
|
||
def with_status(self, *statuses):
|
||
return [
|
||
broadcast for broadcast in self if broadcast.status in statuses
|
||
]
|